THE BEETLES 



137 



or in the foodstuff of the larvae. Both larvae and adults have biting 

 mouth-parts, similar to those of the grasshopper, the structure vary- 

 ing with the food habits of the species. 



The families of beetles are divided into several groups, based 

 largely on the structure of the tarsi and antennae, which aid the 

 student in their identification. The order is primarily divided into 

 the typical beetles (Coleoptera genuine?) y in which the head is nor- 

 mal, and the snout-beetles (Rhynchophora), in which the head is 

 prolonged into a snout, or beak, at the tip of 

 which are the biting mouth-parts. 



THE TYPICAL BEETLES (COLEOPTERA 



GENUINA) 



Four principal sections of the. families of 

 typical beetles are distinguished by the num- 

 ber of segments in the tarsi. 



I. BEETLES WITH FIVE-JOINTED TARSI 



(PENTAMERA] 



The first section is distinguished by all of 

 the tarsi being composed of five segments, 

 and is divided into four tribes according to 

 the structure of the antennae. 



The Carnivorous Beetles (Adephagci) 

 The carnivorous, or predacious, beetles 

 include several families, all of which feed 

 upon other insects and are therefore bene- 

 ficial. The antennae are threadlike, with dis- 

 tinct, cylindrical segments. 



FIG. 190. A tiger-beetle 

 (Cicindelalimbatd]. (Hair 

 line shows natural size) 



(After Bruner) 



The tiger-beetles (Cidndelidae). Along sandy paths, roadsides, rail- 

 road embankments, and in similar open, sunny spots, the tiger- 

 beetles fly up and dart swiftly ahead as one approaches. They 

 are swift runners and stalk their prey on foot. Most of our com- 

 mon species are either a brilliant, metallic green or a brownish- 

 bronze, banded or spotted with yellow. The larvae live in little 

 burrows in the ground, the head appearing at the opening so that 

 the eyes command the surroundings, and any unwary passing insect 

 may be seized with the strong jaws. Toward the tip of the abdomen 



